The Principle of General Relativity, the Restriction to Covariance, and Stanford's Experiment Gravity Probe‐B

It is shown that Einstein's “principle of covariance” has no theoretical basis in physics or observational support beyond what is allowed by the principle of general relativity. Theoretically, Einstein's equivalence principle actually implies that Einstein's physical space has a frame of reference that necessarily has the Euclidean‐like structure and a time coordinate such that the time rate is related to the local clocks. Thus Zhou's experiment on local light speeds correctly challenges Einstein's “principle of covariance.” Examples are provided to support Einstein's equivalence principle and the Maxwell‐Newton approximation (MNA), but reject unrestricted covariance on the grounds of observation. The binary pulsar experiments actually have rejected the Schwarzschild solution. Moreover, since the MNA and the Kerr metric lead to distinct de Sitter precession formulas for Stanford's experiment, Gravity Probe‐B, the claim of gauge invariance is invalid in the first order. This shows unequivocally that Einstein's “principle of covariance” is invalid in physics.